Self-propelled civil engineering machine system with field rover

ABSTRACT

A civil engineering machine has a machine control unit configured to determine data which defines the position and/or orientation of a reference point on the civil engineering machine in relation to a reference system independent of the position and orientation of the civil engineering machine. A geometrical shape to be produced on the ground is preset in either a machine control unit or a field rover control unit. The field rover is used to determine a position of at least one identifiable point of the preset geometrical shape in the independent reference system. Curve data defining a desired curve in the independent reference system, corresponding to the preset shape, is determined at least partially on the basis of the position of the at least one identifiable point of the preset geometrical shape in the independent reference system.

BACKGROUND OF THE INVENTION

The invention relates to a self-propelled civil engineering machine, andin particular a road milling machine, road paver or slipform paver, andto a method of controlling a self-propelled civil engineering machineand in particular a road milling machine, road paver or slipform paver.

DESCRIPTION OF THE PRIOR ART

There are a variety of known kinds of self-propelled civil engineeringmachines. In particular, these machines include the known slipformpavers, road pavers and road milling machines. The characteristicfeature of these self-propelled civil engineering machines is that theyhave a working unit having working means for producing structures on theground or for making changes to the ground.

In the known slipform pavers, the working unit comprises an arrangementfor moulding flowable material and in particular concrete, whicharrangement will be referred to in what follows as a concrete mould.Structures of different types, such as crash barriers and road gutters,can be produced with the concrete mould. A slipform paver is describedEP 1 103 659 B1 (U.S. Pat. No. 6,481,924) for example.

The known road pavers generally have a screed as their working unit. Thescreed is so arranged, at that end of the road paver which is at therear looking in the direction of paving, that it is supported by a lowersliding plate on the material of the road covering being laid and apre-compression of the material thus takes place.

The working unit of the known road milling machines is a millingarrangement which has a milling drum fitted with milling tools, by whichmilling drum material can be milled off the ground over a preset workingwidth.

The known self-propelled civil engineering machines also have a driveunit which has drive means to allow movements in translation and/orrotation to be performed, and a control unit for controlling the driveunit in such a way that the civil engineering machine performs movementsin translation and/or rotation on the ground.

When self-propelled civil engineering machines are controlledautomatically, the problem arises that a preset reference point on thecivil engineering machine has to move precisely along a preset curve inspace on the ground, in order for example to enable a structure of apreset shape to be produced on the ground in the correct position and inthe correct orientation.

A known method of controlling slipform pavers presupposes the use of aguiding wire or line which lays down the desired curve along which thereference point on the civil engineering machine is to move. Elongatedobjects, such as crash barriers or road gutters for example, can beproduced effectively by using a guiding wire or line. However, the useof a guiding wire or line is found to be a disadvantage when structuresof small dimensions, such as cigar-shaped traffic islands for example,which are distinguished by extending for small distances and havingtight radiuses, are to be produced.

It is also known for self-propelled civil engineering machines to becontrolled by using a satellite-based global positioning system (GPS). Acivil engineering machine having a GPS receiver is known from U.S. Pat.No. 5,612,864 for example.

It is a disadvantage that the plotting of the position of an objectusing a master measurement system to control the civil engineeringmachine calls for a great deal of technical cost and complicationbecause the construction project will be complex and the object has tobe fitted into it. What is particularly costly and complicated is theplotting which has to be done of the positions of various referencepoints in the measurement system. This cost and complication can only bejustified for large objects. For small objects on the other hand thecost and complication is disproportionately high.

Another disadvantage of the objects being fitted into the complexbuilding project lies in the fact that in practice, with small objects,allowance often has to be made for fixed points, such for example asexisting hydrants or water outlets on the site, which may possibly notbe situated precisely at the points at which they were entered in theplans. Should the project data not agree with the actual local facts,the project data has to be amended off the site in the office atrelatively high cost and the amended project data then has to be read inagain on the site.

SUMMARY OF THE INVENTION

The object underlying the invention is therefore to provide aself-propelled civil engineering machine, and in particular a roadmilling machine, a road paver or a slipform paver, which can moveautomatically, without any great cost or complication in the plotting ofposition and with high accuracy, along a desired curve extending forrelatively short distances of travel and having tight radiuses. Anotherobject is to specify a method which allows a self-propelled civilengineering machine to be controlled automatically, without any greatcost or complication in the plotting of position and with high accuracy,along a desired curve extending for relatively short distances of traveland having tight radiuses.

The self-propelled civil engineering machine according to the inventionhas a control unit which has means for presetting a given geometricalshape for the structure to be produced or the ground to which changesare to be made. This given shape may for example be a traffic island inthe shape of a cigar. It may be entered or selected by the operator ofthe machine.

The control unit of the self-propelled civil engineering machineaccording to the invention also has means for determining data whichdefines the position and/or orientation of a reference point on thecivil engineering machine in relation to a reference system which isindependent of the position and orientation of the civil engineeringmachine. The reference system (X,Y,Z) independent of the machine-relatedreference system (x,y,z) can be selected as desired, and there is thusno need for the positions of various reference points to be plotted onthe ground.

In one mode of operation of the control system of the civil engineeringmachine, the civil engineering machine is moved to a preset startingpoint on the ground which can be freely selected. At the preset startingpoint the civil engineering machine is aligned in a preset orientation.The position and orientation of the object are thus laid down.Consequently, the object can always be optimally positioned on theground with due allowance made for any possible fixed points. Thestarting point may for example be sited at the corner of a gutteralready present on the ground whose position need not exactly correspondto the layout plan.

As well as this, the control unit of the civil engineering machine alsohas means for determining data defining a desired curve, the desiredcurve being the curve along which the reference point (R) on the civilengineering machine is to move in the reference system (X, Y, Z)independent of the position and orientation of the civil engineeringmachine. The means for determining data defining the desired curve areso designed that the data defining the desired curve is determined onthe basis of the preset geometrical shape of the structure to beproduced or the ground to which changes are to be made and on the basisof the position and orientation of the reference point (R) on the civilengineering machine in the reference system (X, Y, Z) independent of theposition and orientation of the civil engineering machine.

The data which defines the desired curve may be the distance covered bythe desired curve and/or its curvature. This data is dependent on theshape of the object.

In a preferred embodiment, the means for controlling the drive unit areso designed that the drive unit is so controlled, as a function of theposition and orientation of the reference point in the reference systemindependent of the position and orientation of the civil engineeringmachine, that the distance between the desired position of the civilengineering machine, as defined by the desired curve, and its actualposition, and/or the difference in direction between the desireddirection, as defined by the desired curve, and the actual direction, isminimal. The control algorithms required for this purpose are well knownto the person skilled in the art.

An embodiment of the invention which is a particular preference makesprovision for use to be made of a satellite-based global positioningsystem (GPS) to determine the position and/or orientation of thereference point on the civil engineering machine. The reference system(X,Y,Z) independent of the position and orientation of the civilengineering machine is thus the reference system of the satellite-basedglobal positioning system, whose position and direction relative to themachine-related reference system (x,y,z) constantly change as the civilengineering machine moves over the ground. The civil engineering machinehas a first and a second DGPS receiver for decoding the GPS satellitesignals from the satellite-based global positioning system andcorrecting signals from a reference station for determining the positionand/or orientation of the civil engineering machine, the first andsecond DGPS receivers being arranged in different positions on the civilengineering machine.

However, rather than by means of a satellite-based global positioningsystem, the position and/or orientation of the reference point may alsobe determined with a non-satellite measurement system. The only thingthat is crucial is for the control unit to receive data defining theposition and orientation of the reference point in the reference system(X,Y,Z) independent of the civil engineering machine.

In a further preferred embodiment, the control unit has an input unithaving means (7B) for the input of parameters which define thegeometrical shape of the structure to be produced or the ground to whichchanges are to be made. These parameters may for example be parameterswhich define the length of a straight line and/or the radius of an arcof a circle. It is assumed in this case that the object can be brokendown into straight lines and arcs. This can be done for example in thecase of a traffic island in the shape of a cigar. However, it is alsopossible for other geometrical figures to be defined by the parameters.

In a further preferred embodiment, the control unit has an input unithaving means for selecting one geometrical shape from a plurality ofpreset geometrical shapes, the plurality of geometrical shapes beingstored in a storage unit which co-operates with the input unit. Theadvantage of this is that the data defining the geometrical shape doesnot have to be created afresh and instead recourse may be had to datasets which have already been created. A choice may for example be madebetween a circle and a cigar shape as an object.

A further embodiment which is a particular preference makes provisionfor means for modifying a preset geometrical shape. The advantage thatthis has is that the shape of a cigar for example may be selected andthe dimensions of the cigar can then be adjusted to suit the actualrequirements on the site.

In a further embodiment, a field rover is provided which may be used todetermine some or all of the curve data in the independent referencesystem (X,Y,Z). The field rover may include a rover control unit havinga rover shape selection component, a rover position data determinationcomponent, and a rover curve data determination component.

In another embodiment a method of controlling a self-propelled civilengineering machine is provided wherein a field rover is utilized todetermine a position of at least one identifiable point of a presetgeometrical shape in a reference system independent of the position andorientation of the civil engineering machine. Then curve data defining adesired curve is determined in part on the basis of the position of theat least one identifiable point of the preset geometrical shape asdetermined by the rover.

In another embodiment a self-propelled civil engineering machine systemincludes a civil engineering machine and a field rover. The civilengineering machine may include a machine chassis, a working unitarranged on the chassis, a drive unit, and a machine control unit. Thefield rover may include a rover control unit including a rover shapeselection component. Each of the following components is included in atleast one of the machine control unit and the rover control unit:

-   -   a shape selection component operable to preset a geometrical        shape for the structure to be produced or for the ground to        which changes are to be made;    -   a machine position data determination component operable to        determine position data to define the position and/or        orientation of a reference point on the civil engineering        machine in relation to the reference system which is independent        of the position and orientation of the civil engineering        machine;    -   a curve data determination component operable to determine curve        data to define a desired curve based on the preset geometrical        shape of the structure to be produced or the ground to which        changes are to be made and based on a desired position and        orientation of the preset geometrical shape in the reference        system independent of the position and orientation of the civil        engineering machine, the desired curve being that curve along        which the reference point on the civil engineering machine is to        move in the reference system independent of the position and        orientation of the civil engineering machine; and    -   a drive control component operable to control the drive unit, as        a function of the curve data defining the desired curve, in such        a way that the reference point on the civil engineering machine        moves along the desired curve.

In another embodiment a self-propelled civil engineering machine systemincludes a civil engineering machine including a machine chassis and aworking unit arranged on the chassis. A drive unit drives the machine. Amachine control unit is operable to control the movement of the machine.The machine control unit includes a machine data determination componentand a drive control component. The machine data determination componentmay include a field rover mounted on the civil engineering machine, thefield rover being removable from the civil engineering machine so thatthe field rover may be used separately to survey positions on theground.

In another embodiment a hand held field rover apparatus includes acontrol unit having a position data determination component, a shapefitting component and a shape storing component. The shape fittingcomponent is configured to define a defined shape corresponding to aseries of surveyed positions, the shape fitting component beingconfigured such that a user may select for at least some of the surveyedpositions whether the positions are part of a straight line portion orpart of a curved portion of the defined shape.

In another embodiment the shape fitting component may include a shapesmoothing component configured such that the user may selectively useposition data in defining the defined shape. The shape smoothingcomponent may be configured such that the user may select for eachsurveyed position to use the position data only with regard to theelevation position or the horizontal position of the defined shape. Theshape smoothing component may be configured such that the user mayselect for each surveyed position to not include the position data indefining the defined shape. The determinations for use of position datamay be made in response to queries posed by the shape fitting component.

In another embodiment a hand held field rover survey apparatus includesa control unit including a shape selection component, a position datadetermination component and a curve data determination component.

In another embodiment a method of surveying using a hand held fieldrover is provided. The field rover includes a support rod having a lowerend for engaging a ground surface and a position sensor mounted on thesupport rod. The field rover is used to determine a series of surveyedpositions of a geometrical shape for a structure to be produced or theground to which changes are to be made. For at least some of thesurveyed positions a selection is made whether the positions are part ofa straight line portion or part of a curved portion of the geometricalshape. A defined shape is then defined corresponding to the series ofsurveyed positions.

Embodiments of the invention will be explained in detail in what followsby reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side view of an embodiment of slipform paver.

FIG. 2 is a side view of an embodiment of road milling machine.

FIG. 3 shows a machine co-ordinate system related to a civil engineeringmachine together with the civil engineering machine, which is merelyindicated.

FIG. 4 shows a measurement co-ordinate system (X,Y,Z) independent of theposition and orientation of the civil engineering machine together withthe machine related co-ordinate system (x,y,z) and civil engineeringmachine which are shown in FIG. 3 .

FIG. 5 shows the graph curves for curvature and direction for an objectin the shape of a cigar.

FIG. 6 is a view of the geometrical shape defining a cigar-shaped objectfor controlling the civil engineering machine, before it is transposedinto the measurement co-ordinate system (X,Y,Z).

FIG. 7 is a view of the desired curve defining a cigar-shaped object forcontrolling the civil engineering machine, after it has been transposedinto the measurement co-ordinate system (X,Y,Z).

FIG. 8 shows the distance between the desired position of the civilengineering machine as defined by the desired curve and its actualposition.

FIG. 9 shows the difference in direction between the desired directionof the civil engineering machine as defined by the desired curve and itsactual direction.

FIG. 10 is a schematic illustration of a civil engineering machinesystem including a GPS field rover.

FIG. 11 is a schematic illustration similar to FIG. 7 , showing how thelocation of the preset shape in the independent reference system can bedefined by the location of one point of the shape plus an orientation ofthe shape, or by the location of two points of the shape.

FIG. 12 is a schematic flow chart representation of a shape fittingcomponent of the field rover control unit.

FIG. 13 is a screen shot of a display screen of the field rover showingdisplay of surveyed points and an input screen. In FIG. 13 a first pointhas been surveyed.

FIG. 14 is another screen shot similar to FIG. 13 , wherein a secondpoint has been surveyed and a straight line portion of a defined shapehas been displayed.

FIG. 15 is another screen shot illustrating the addition of four moresurveyed points defining a second straight line portion and a curvedportion.

FIG. 16 is another screen shot illustrating the addition of a seventhsurveyed point defining a third straight line portion.

FIG. 17 is a schematic illustration similar to FIG. 10 showing analternative embodiment wherein the field rover may be mounted on thecivil engineering machine for use as one of the receivers of the civilengineering machine.

FIG. 18 is a schematic illustration similar to FIG. 17 showing anotheralternative embodiment wherein the rover control unit of the field roveris used as the machine control unit of the civil engineering machine.

DETAILED DESCRIPTION

FIG. 1 is a side view of, as an example of a self-propelled civilengineering machine, a slipform paver which is described in detail in EP1 103 659 B1 (U.S. Pat. No. 6,481,924). Because slipform pavers as suchare part of the prior art, all that will be described here are thosecomponents of the civil engineering machine which are material to theinvention.

The slipform paver 1 has a chassis 2 which is carried by running gear 3.The running gear 3 has two front and two rear track-laying running gearunits 4A, 4B which are fastened to front and rear lifting pillars 5A,5B. The direction of working (direction of travel) of the slipform paveris identified by an arrow A.

The track-laying running gear units 4A, 4B and the lifting pillars 5A,5B are parts of a drive unit of the slipform paver which has drive meansto allow the civil engineering machine to carry out movements intranslation and/or rotation on the ground. By raising and lowering thelifting pillars 5A, 5B, the chassis 2 of the machine can be movedrelative to the ground to adjust its height and inclination. The civilengineering machine can be moved backwards and forwards by thetrack-laying running gear units 4A, 4B. The civil engineering machinethus has three degrees of freedom in translation and three degrees offreedom in rotation.

The slipform paver 1 has an arrangement 6, which is only indicated, formoulding concrete which will be referred to in what follows as aconcrete mould. The concrete mould is part of a working unit which hasworking means for producing a structure 10 of a preset shape on theground.

FIG. 2 is a side view of, as a further example of a self-propelled civilengineering machine, a road milling machine. Once again, the roadmilling machine 1 too has a chassis 2 which is carried by running gear3. The running gear 3 has two front and two rear track-laying runninggear units 4A, 4B which are fastened to front and rear lifting pillars5A, 5B. The road milling machine has a working unit which has workingmeans to make changes to the ground. This working unit is a millingarrangement 6 which has a milling drum 6A fitted with milling tools.

FIG. 3 shows the self-propelled civil engineering machine in amachine-related Cartesian co-ordinate system (x, y, z). The civilengineering machine may be a slipform paver, a road milling machine orany other civil engineering machine which has an appropriate workingunit. The present embodiment is a slipform paver 1 which has a concretemould 6. The slipform paver 1 and the concrete mould 6 are merelyindicated. It has the chassis 2, having the track-laying running gearunits 4A, 4B, and the concrete mould 6.

The origin of the machine co-ordinate system is at a reference point Ron the slipform paver 1, what is laid down as the reference point Rbeing that edge of the concrete mould 6 which is on the inside and atthe rear in the direction of travel. This edge corresponds to the outerboundary of the structure 10 to be produced. In the machine co-ordinatesystem, the reference point R is determined as follows:R=xR,yR,zR=0,0,0

The machine co-ordinate system is clearly defined by six degrees offreedom, with the lengths of travel dx, dy, dz defining the movements intranslation and the angles ω, φ, κ defining the three movements inrotation.

To simplify things, it will be assumed that the civil engineeringmachine is standing on flat ground and is not inclined. The angles ω andκ in rotation are thus each equal to zero. The machine co-ordinatesystem and the civil engineering machine are aligned to one another insuch a way that the angle φ in rotation is equal to zero as well.

It will also be assumed that the bottom edge of the concrete mould 6 isresting on the ground. This lays it down that the height zR of thereference point R is not to change as the civil engineering machinemoves over the flat ground.

FIG. 4 shows the machine co-ordinate system together with a Cartesianreference system, independent of the machine co-ordinate system (x, y,z), which will be referred to in what follows as the measurementco-ordinate system (X, Y, Z). The measurement co-ordinate system (X, Y,Z) may be selected at random. It remains in the same position andorientation as the civil engineering machine moves.

To control the drive unit, the civil engineering machine has a controlunit 7 which is merely indicated. The control unit 7 controls the drivemeans of the drive unit in such a way that the civil engineering machineperforms the requisite movements in translation and/or rotation on theground to enable it to produce the structure 10 or make changes to theground. The control unit 7 comprises all the components which arerequired to perform calculating operations and to generate controlsignals for the drive means of the drive unit. It may form aself-contained unit or it may be part of the central control system ofthe civil engineering machine.

To allow the drive unit to be controlled, the position and/ororientation of the reference point R of the civil engineering machine inthe machine co-ordinate system (x, y, z) is transposed into themeasurement co-ordinate system (X, Y, Z) independent of the movements ofthe civil engineering machine.

In the present embodiment, the position and orientation of the referencepoint R are determined using a satellite-based global positioning system(GPS), which is only indicated in FIG. 4 . However, rather than asatellite-based positioning system what may also be used is anon-satellite terrestrial measuring system (a total station). Becausethe requirements for the accuracy with which position and orientationare determined are stringent ones, what is preferably used is thatsatellite-based global positioning system which is known as thedifferential global positioning system (DGPS). The GPS-based method ofdetermining orientation is based in this case on the measurement ofposition by two DGPS receivers which are arranged at different pointsS1, S2 on the civil engineering machine.

The two DPGS receivers S1 and S2 are merely indicated in FIGS. 3 and 4 .The case assumed is the more general one where the DGPS receiver S1 andthe DGPS receiver S2 are situated near the origin of the machineco-ordinate system in which the reference point R is sited, the positionand orientation of which reference point R are determined in themeasurement co-ordinate system.

The positions of the DGPS receivers S1 and S2 are determined in themachine co-ordinate system (x, y, z) by the co-ordinates S1=xs1, ys1,zs1 and S2=xs2, ys2, zs2. In the measurement co-ordinate system (X, Y,Z), the positions of the DGPS receivers S1 and S2 are determined byS1=XS1, YS1, ZS1 and S2=XS2, YS2, ZS2.

By using the two DGPS receivers S1 and S2, the control unit 7 employsthe GPS system to determine data which defines the position of the DGPSreceivers. From this data on position, the control unit 7 thencalculates the position and orientation of the reference point R on thecivil engineering machine near to which the two DGPS receivers aresituated. For this purpose, the control unit 7 performs a transformationwith the rotation matrix R to transform the co-ordinates at the pointsS1 and S2 which were measured in the measurement co-ordinate system (X,Y, Z) by the DGPS receivers S1 and S2 to give the reference point R

$\begin{bmatrix}{\Delta X} \\{\Delta Y} \\{\Delta Z}\end{bmatrix} = \begin{bmatrix}{{{XS}1} - {{xs}1}} \\{{{YS}1} - {{ys}1}} \\{{{ZS}1} - {{zs}1}}\end{bmatrix}$ $\left. \lbrack\begin{matrix}X \\Y \\Z\end{matrix} \right\rbrack = {{\lbrack R\rbrack\ \begin{bmatrix}x \\y \\z\end{bmatrix}} + \begin{bmatrix}{\Delta X} \\{\Delta Y} \\{\Delta Z}\end{bmatrix}}$ $\left. \lbrack\begin{matrix}X \\Y \\Z\end{matrix} \right\rbrack = {{\begin{bmatrix}{{\cos\phi} - {\sin\phi}} & 0 \\{\sin{\phi\cos}\phi} & 0 \\{00} & 1\end{bmatrix}\begin{bmatrix}x \\y \\z\end{bmatrix}} + \begin{bmatrix}{\Delta X} \\{\Delta Y} \\{\Delta Z}\end{bmatrix}}$

The result is that the control unit determines the measurementco-ordinates of the reference point R on the concrete mould 6 of theslipform paver 1 in the measurement co-ordinate system (X, Y, Z):

$R = \begin{bmatrix}{Xr} \\{Yr} \\{Zr}\end{bmatrix}$

The control unit uses the following equation to calculate the angle Φgiving the direction of the civil engineering machine from theco-ordinates (XS2, XS1; YS2, YS1) of the measured points S1 and S2:Φ=arctan(XS2−XS1/YS2−YS1)

The control unit 7 controls the drive unit of the civil engineeringmachine in such a way that the civil engineering machine moves along apreset desired curve, i.e. the reference point R on the civilengineering machine moves along the desired curve.

In its general form, the desired curve can be defined as follows as afunction of distance travelled and curvature:

$\begin{bmatrix}X \\Y\end{bmatrix} = {{f(L)} = {{\int_{\sin\alpha}^{\cos\alpha}({dl})} = \begin{bmatrix}{X0} \\{Y0}\end{bmatrix}}}$ where α = ∫K(dl).

The curvature K is defined by K=1/R.

As an alternative to the system just described using two DGPS receivers,it is also to devise a control system using a single DGPS receiver. Sucha control system would lock the rear drive tracks 4B in a straightforward position. The machine could then automatically follow a curvebased on the data of just one DGPS sensor because there is a fixedcenter of rotation at the locked tracks. In this case the orientation ofthe machine could be determined by observing the position data of theone DGPS sensor, the alignment of the steerable front tracks 4A and thedistance driven.

In the present embodiment, the slipform paver is to produce a trafficisland in the shape of a “cigar”. The geometrical shape of the cigar isdefined by a curve which comprises two parallel distances travelled andtwo arcs of a circle. What will be described in what follows will beonly that part of the curve which comprises the initial straight lineand the first semi-circular arc.

In the embodiment of the cigar, the curvature on the initial straightline is equal to zero. When the reference point R on the civilengineering machine moves along the first arc of a circle, the curvatureis constant. Once the civil engineering machine has ceased to move alongthe arc, the curvature once again becomes zero.

FIG. 5 shows the graph plot 9 for curvature and the graph plot 8 fordirection for the slipform paver when producing a cigar whosegeometrical shape is defined by a straight line of a length of 2 m andby a semi-circular arc whose radius is 2 m. The length and radiusconstitute in this case two parameters by which the geometrical shape ofthe cigar is preset. It will be clear that the graph plot for directionchanges as the civil engineering machine enters the arc.

The operator of the civil engineering machine first presets a givengeometrical shape such as the shape of a cigar for example. The operatoris free as to the geometrical shape he presets. FIG. 6 shows thegeometrical shape which is defined by a straight line “a” and asemi-circular arc “b”. Simply to make things clear, the geometricalshape of the cigar has been shown in a grid which relates to the machineco-ordinate system (x,y,z). The measurement co-ordinate system (X, Y, Z)has therefore been indicated in FIG. 6 only to show the relationshipbetween the machine and measurement co-ordinate systems.

The control system according to the invention relies on a starting pointat which the production of the structure 10, such as a cigar forexample, begins first being freely selected for the slipform paver onthe ground. This starting point corresponds to the origin of the machineco-ordinate system, i.e. the reference point R (FIG. 6 ). The startingpoint may for example be situated next to a fixed point which is preseton the ground, such as a water inlet for example. The starting pointdefines the place at which the structure 10, such as the cigar forexample, is to be produced. The orientation of the civil engineeringmachine is preset freely at the starting point, thus laying down thedirection in which the structure 10, such as the cigar for example, isto extend.

The civil engineering machine is now driven to the selected startingpoint and is aligned in the preset orientation. This process is notautomated. The automated control of the civil engineering machine thentakes place.

The civil engineering machine having been positioned and aligned, thecontrol unit 7 determines for the starting point the data which definesthe position and orientation of the reference point R in the measurementco-ordinate system (X, Y, Z). This data which defines the position andorientation of the reference point R may be referred to as positiondata. For the subsequent control, the preset geometrical shape, such asthe cigar for example, then has to be transposed to the measurementco-ordinate system (X, Y, Z). On the basis of the preset geometricalshape of the structure to be produced or of the ground to which changesare to be made and on the basis of the position and orientation of thereference point R on the civil engineering machine in the measurementco-ordinate system (X, Y, Z) which is independent of the position andorientation of the civil engineering machine, the control unit 7determines data which defines a desired curve, the desired curve beingthat curve along which the reference point R on the civil engineeringmachine is to move in the measurement co-ordinate system (X, Y, Z). Thedata defining the desired curve may be referred to as curve data.

FIGS. 6 and 7 show the transfer of the freely preset geometrical shape(FIG. 6 ) to the measurement co-ordinate system (X,Y,Z) (FIG. 7 ), toallow the desired curve which defines the desired positions of thereference point in the measurement co-ordinate system (X, Y, Z) to belaid down.

The position and orientation of the reference point R on the civilengineering machine at the starting point having been determined and thedesired curve having been laid down, the control unit 7 puts the civilengineering machine into operation. The control unit now determines,continuously or at discrete increments of time, the actual position (Xr,Yr) and actual direction (Φ) of the reference point R on the civilengineering machine in the measurement co-ordinate system (X, Y, Z). Inso doing the control unit each time calculates the distance D betweenthe desired position P and the actual position (Xr, Yr) and thedifference in direction ΔΦ between the desired direction α and theactual direction Φ.

Using a preset control algorithm, a drive control component of thecontrol unit 7 calculates from the distance D and the difference indirection ΔΦ the value at the time of the manipulated variable for thedrive means of the drive unit in such a way that the distance D and thedifference in direction ΔΦ are minimal, i.e. in such a way that thereference point on the civil engineering machine moves along the desiredcurve. Control algorithms of this kind are well known to the personskilled in the art.

FIG. 8 shows the distance D between the desired position of a point onthe desired curve and the actual position (Xr, Yr) of the referencepoint R, while FIG. 9 shows the difference in direction ΔΦ between thedesired direction α and the actual direction Φ at a point on the desiredcurve. The correction to the steering is found as a function of thedistance D and the difference in direction ΔΦ (correction tosteering=f(D, ΔΦ).

For the presetting of the geometrical shape, i.e. for the presetting ofa given object, the control unit has an input unit 7A which is onceagain merely indicated. The input unit 7A may also be referred to as ashape selection component 7A. In one embodiment, the input unit 7A hasmeans 7B in the form of, for example, a keyboard or a touch screen. Fromthe keyboard or touch screen 7B, the operator of the machine can entervarious parameters which define the geometrical shape. The operator mayfor example enter the length of the straight line and the radius of thearc for a cigar. The input unit 7A may also have means 7B, such forexample as a keyboard or touch screen once again, to enable onegeometrical shape which defines the desired object to be selected from aplurality of geometrical shapes which are stored in a memory unit 7C ofthe control unit. As well as for the input of parameters and/or theselection of geometrical shapes, a further embodiment of the controlunit 7 also makes provision for the modification of a geometrical shapewhich has been entered or selected. For example, a cigar whose straightlines are of a preset length and whose arcs are of a preset radius maybe selected and then, by entering new parameters for the length of thestraight lines and/or the radius of the arcs from the keyboard or touchscreen 7B, the cigar which was selected may be adjusted to suit theparticular requirements which exist at the site, the cigar being madesmaller or larger for example and in particular its width or lengthbeing changed.

As well as this, the input unit 7A also has means 7D, in the form of aswitch or push-button 7D for example, by which the civil engineeringmachine can be put into operation on the ground after the positioningand alignment. A switch or push-button 7D may also be provided on theinput unit 7A to enable the civil engineering machine to be stoppedbefore it has moved for the entire length of the desired curve. Thecivil engineering machine having been stopped, new parameters may, forexample, then be entered from the keyboard or touch screen 7B to changethe path followed by the curve and for example to change the height ofthe object being produced.

Alternative Techniques

The system described above provides a great deal of flexibility increating and using preset geometrical shapes to be applied to selectedactual ground locations.

More generally, the control unit described above can be described asincluding:

a shape selection component operable to preset a geometrical shape forthe structure to be produced or for the ground to which changes aremade;

a position data determination component operable to determine positiondata to define the position and/or orientation of a reference point onthe civil engineering machine in relation to a reference system which isindependent of the position and orientation of the civil engineeringmachine;

a curve data determination component operable to determine curve data todefine a desired curve based on the preset geometrical shape of thestructure to be produced or the ground to which changes are to be madeand based on a desired position and orientation of the presetgeometrical shape in the reference system independent of the positionand orientation of the civil engineering machine, the desired curvebeing that curve along which the reference point on the civilengineering machine is to move in the reference system independent ofthe position and orientation of the civil engineering machine; and

a drive control component operable to control the drive unit, as afunction of the curve data defining the desired curve, in such a waythat the reference point on the civil engineering machine moves alongthe desired curve.

One way to determine the desired position and orientation of the presetgeometrical shape in the reference system independent of the positionand orientation of the civil engineering machine is the method describedin detail above wherein the shape is first defined in themachine-related coordinate system (x,y,z) and is then transformed intothe reference system independent of the position and orientation of thecivil engineering machine. In that case, the desired position andorientation of the preset geometrical shape is the position in which thestarting point and orientation corresponds to the current location ofthe reference point R on the civil engineering machine 1 and the currentorientation of the civil engineering machine in the independentreference system (X,Y,Z). In that case, the machine is already locatedat a known point and in a known orientation on the desired curve, andthe drive control component 7D may be activated to move the machinealong the desired curve.

It will be appreciated that identifying the current position andorientation of the reference point R on the civil engineering machine 1as a known point and orientation on the desired curve is only one way todetermine the curve data defining the desired curve. The curve data forthe desired curve can be determined by any technique that will definethe location and orientation of the preset shape in the reference systemindependent of the position and orientation of the civil engineeringmachine.

In general, once the preset shape has been selected, it is necessary toeither identify the location within the independent reference system(X,Y,Z) of at least two identifiable points of the preset shape, or toidentify the location within the independent reference system of oneidentifiable point of the preset shape and identify the orientation ofthe preset shape within the independent reference system. For example inFIG. 11 a cigar shape is shown defined by two straight line portions andtwo semi-circular portions of radius “r” having centers M1 and M2. Itwill be appreciated in viewing FIG. 11 that the location and orientationof the cigar shape curve there shown can be defined by identifying thelocation in the independent reference system of any two identifiablepoints on the curve, or by identifying the location of one point plusthe orientation of the shape. That orientation may be described by thedirection along the shape at the identified point. If the point is on acurved portion of the shape, the direction is preferably defined as thetangent of the curve.

For example, with reference to FIG. 11 , the system described above candetermine the curve data of the desired curve by the operator inputtinginformation defining the location of a selected point S100′ on thepreset shape within the independent reference system, and informationdefining the selected orientation of the preset shape within theindependent reference system such as the angle 109 shown in FIG. 11 .Then using that input information the data defining the preset shape canbe transformed into data defining the desired curve in the independentreference system in the same way as described above for use of thecurrent position and orientation of the reference point R of the civilengineering machine 1 as the input data. This input data may for examplebe determined on the job site by identifying the desired location of apoint on the desired curve within the independent reference system(X,Y,Z). This may be accomplished by surveying the location of a desiredstarting point for the preset shape within the independent referencesystem, for example the point S100′. The surveying may be accomplishedvia a GPS field rover as further described below, or by any othersuitable surveying technology. The desired orientation of the presetshape within the independent reference system may also be similarlydetermined on the job site.

Also, if the desired location in the independent reference system of twopoints of the preset shape can be identified, that information can thenbe used to transform the preset shape into curve data defining thedesired curve in the independent reference system. In the example ofFIG. 11 the two points could be the beginning and ending points S100′and S100″ of one of the straight sections of the cigar shape as shown inFIG. 11 . The desired location of those two points may be identified inthe independent reference system, for example by using the field rover.The information identifying those two points within the independentreference system can then be used as the reference points to transformthe data defining the preset shape into curve data defining the desiredcurve within the independent reference system.

In a situation like either of the alternative examples just described,wherein the reference point of the civil engineering machine is notalready located at a known location on the desired curve, it isnecessary to move the civil engineering machine to the desired startingpoint and to orient the civil engineering machine in the desiredorientation before beginning the paving or milling or other constructionoperation of the civil engineering machine. This movement of the civilengineering machine to the desired starting point and orientation canalso be automated. The control unit 7 can control the movement of thecivil engineering machine from any initial location to any desired pointand orientation on the desired curve in the same manner as describedabove with regard to FIGS. 8 and 9 . In practice, the machine operatorwill typically drive the machine to a location near to the desiredcurve, and then allow the automated control unit 7 to take over and movethe machine precisely into a starting position on the desired curve.

Use of a Field Rover

One way to conveniently gather and input the information defining thedesired locations in the independent reference system of correspondingpoints on the preset shape is to use a GPS field rover to survey thedesired location of those points.

It is particularly desirable to use a GPS field rover including acontrol unit which substantially duplicates the shape selectioncomponent, the position data determination component and the curve datadetermination component of the control unit of the civil engineeringmachine. This allows the GPS field rover to be used to generate thecurve data defining the desired curve in advance of moving the civilengineering machine to the field location. Then the curve data cansimply be transferred into the control unit of the civil engineeringmachine and used to control the operation of the civil engineeringmachine.

A schematic representation of a civil engineering machine system 101including a field rover 100 is shown in FIG. 10 . The rover 100 includesa rod 102. A lower end 104 of the rod is placed on a location on theground surface for which the GPS coordinates are to be determined. A GPSreceiver S100 is located at the upper end of the rod 102 and may beconnected to a rover control unit 107 via electrical connection 105.Optionally, the rover control unit may be embodied as a separate handheld control unit 107′ connected via wireless connection 105′ to thereceiver S100 as indicated in FIG. 10 . The rover control unit 107 maysubstantially duplicate the shape selection component, the position datadetermination component, and the curve data determination component ofthe control unit of the civil engineering machine. The rover controlunit 107 includes a rover position data determination component 107Ewhich receives the signals from the GPS receiver S100 to determineposition data to define the position of the field rover 100 in relationto the independent reference system (X,Y,Z). The field rover 100 mayalso include a radio 103 for communicating with a GPS base station, anda battery 106 to provide power.

The rover 100 may also be constructed for use with any of the otherlocation technologies described above. For example the GPS receiver S100may be replaced with a prism for use with a total station. Or othersatellite based location technologies may be used.

Thus for the pre-setting of the geometrical shape, i.e. for thepre-setting of a given object, the rover control unit 107 has a roverinput unit 107A. The rover input unit 107A may also be referred to as ashape selection component 107A. In one embodiment, the rover input unit107A has means 107B in the form of, for example, a keyboard or a touchscreen. From the keyboard or touch screen 107B, the operator of therover can enter various parameters which define the geometrical shape.The operator may for example enter the length of the straight line andthe radius of the arc for a cigar. The rover input unit 107A may alsohave means 107B, such for example as a keyboard or touch screen onceagain, to enable one geometrical shape which defines the desired objectto be selected from a plurality of geometrical shapes which are storedin a rover memory unit 107C of the rover control unit. As well as forthe input of parameters and/or the selection of geometrical shapes, afurther embodiment of the rover control unit 107 also makes provisionfor the modification of a geometrical shape which has been entered orselected. For example, a cigar whose straight lines are of a presetlength and whose arcs are of a preset radius may be selected and then,by entering new parameters for the length of the straight lines and/orthe radius of the arcs from the rover keyboard or touch screen 107B, thecigar which was selected may be adjusted to suit the particularrequirements which exist at the site, the cigar being made smaller orlarger for example and in particular its width or length being changed.

The rover control unit 107 has the same capabilities as described abovefor the machine control unit 7, with regard to the determination ofcurve data to be used by the machine control unit 7. Thus the rovercontrol unit 107 can take a preset shape and then use informationrepresenting the desired location in the independent reference system ofat least two identifiable points of the shape or of one point and theorientation of the shape, to create curve data completely identifyingthe location of the shape in the independent reference system. Thisportion of the rover control unit 107 comprises a rover curve datadetermination component.

The rover control unit 107 has an input/output port 108 which allowscurve data determined via the rover control unit 107 to be downloaded toa digital media such as a memory stick which can then be used totransfer the curve data to the control unit 7 of the civil engineeringmachine. Furthermore, additional predefined geometrical shapes and/orpre-processed GPS data can be loaded into the rover memory unit 107C.The data may also be transferred by wireless means or any other suitabletechnology.

The addition to the civil engineering machine system 101 of the separatefield rover 100 having the rover control unit 107 duplicating many ofthe capabilities of the shape selection component, the position datadetermination component, and the curve data determination component,greatly increases the flexibility of the system. This allows selectedsteps to be performed in the machine control unit 7 or in the rovercontrol unit 107, whichever is most convenient.

In one embodiment, as described above with regard to FIGS. 1-9 , themachine control unit 7 can be utilized to perform all the functions. Inthat case the position and orientation of the machine are used to definethe position and orientation of the preset shape in the independentreference system (X,Y,Z).

In another embodiment, the field rover 100 can be utilized to gatheronly partial data for the desired curve location. For example the fieldrover could be used to survey the location of a starting point S100′,which location could then be used by the machine control unit 7 todetermine curve data in the independent reference system. The machinecould then be driven to the surveyed starting point.

In another embodiment the field rover 100 can be utilized to completelydetermine the curve data in the independent reference system, and thatcurve data can be transferred to the machine control unit.

The combined system of the civil engineering machine with its machinecontrol unit 7 and the field rover 100 with its rover control unit 107provides the ability to deal with any situation which may be encounteredin the field.

For example, at a large sophisticated job site, the entire site may havebeen surveyed and designed in a state plane coordinate system, and thesurveyor may have provided pre-processed GPS coordinate files definingall of the structures to be paved on the job site. If thosepre-processed files are accurate, they may be loaded into the machinecontrol unit 7 and executed without modification. If the pre-processedGPS coordinate file is unusable because of error or because of thepresence of some unexpected obstacle on the ground, the machine operatorcan edit the file in the machine control unit 7 or in the rover controlunit 107 to make it usable. Furthermore, the pre-processed file can beused simply as a shape file, and a new GPS coordinate file may begenerated by the machine control unit 7 or by the rover control unit 107to move that shape to any desired location and orientation within theindependent reference system.

In another example, the designer of the job site may have pre-surveyedthe site and placed pins or stakes in the ground identifying thelocations of a series of surveyed points along the ground surface, whichpoints identify the desired curve on the ground surface. In the priorart such pre-surveyed points are utilized to build a stringline to guidethe civil engineering machine. With the present system, the field rover100 may be utilized to create a virtual stringline by using the rover toidentify the locations of those pre-surveyed points, and then to definethe desired curve within the independent reference system. The curvedata defining that virtual stringline may then be transferred into themachine control unit 7.

In another example the job site designer may have only provided a paperplan specifying the desired locations of various structures on thejobsite. There may be no pre-processed GPS files and no pre-surveyedground locations. In that situation either the machine control unit 7 orthe rover control unit 107, or a combination of both, may be utilized todetermine the curve data defining the desired curve in the independentreference system.

In still another example, there may not even be a paper plan. There mayjust be a job site, and structures may be designed on site by selectingor creating a preset shape, and then determining the curve data todefine the desired curve for that shape within the independent referencesystem. That can be done with either the machine control unit 7 or therover control unit 107, or a combination of both, in any of the mannersdescribed above.

In general the machine control unit 7 and the rover control unit 107together should collectively provide the various control unit componentsdescribed above. The machine control unit 7 and the rover control unit107 may completely duplicate all functions to provide redundantcapability. Or selected control unit components may be provided byeither one or both of the control units.

The minimum capability that should be present in the rover control unit107 is to provide the rover position data determination component. Therover control unit 107 may also provide the shape selection componentand/or the curve data determination component.

Use of Field Rover to Design Shapes

The rover 100 can also be utilized to easily create new complex shapes.The rover can survey a series of points on a ground surface identifyingthe shape which is to be created. The rover control unit 107 can thendefine a shape based upon the series of points. That shape can then besaved in the memory 107C for subsequent use, and it can also betransferred to the machine control unit 7.

In order to create these new complex shapes, the rover control unit 107may include a shape fitting component 110 embodied in software which maybe stored in the memory 107C. The functionality of the shape fittingcomponent 110 is schematically illustrated in the flow chart of FIG. 12. Various representative screen shots illustrating embodiments of thetouch screen 107B corresponding to various features of the shape fittingcomponent 110 are illustrated in FIGS. 13-16 .

The shape fitting component 110 may be generally described as a shapefitting component configured to define a defined shape corresponding toa series of surveyed positions. As is further explained below, the shapefitting component 110 is preferably configured such that a user mayselect for at least some of the surveyed positions whether the positionsare part of a straight line portion of part of a curved portion of thedefined shape. After definition of the defined shape, the defined shapemay be stored in memory 107C. The shape fitting component 110 mayinclude a shape smoothing component 112 configured such that the usermay selectively use position data in defining the defined shape. Theshape smoothing component is configured such that the user may selectfor each surveyed position, or at least some of the surveyed positions,to not include the position data in defining the defined shape or to usethe position data for the surveyed position only with regard to eitherelevation position or horizontal position of the defined shape.

An example of the manner of use of the shape fitting component 110 inassociation with the display and input functions of the touch screen107B as illustrated in FIGS. 13-16 will now be described.

Starting for example with a straight line curb with uniform slope, ifthe user knows where the curb is to be located in the field, the fieldrover 100 may be placed on the ground at the starting point of the curb.

FIG. 13 illustrates the display of the touch screen 107B having on theleft hand side a display 114 of the surveyed points and subsequently ofthe shape defined by those points, and having on the right hand side 116an input screen. In FIG. 13 the first surveyed point is indicated by thenumeral 1. After measuring the first point 1, the user is prompted todecide whether the point is part of a straight line portion or a curvedportion of the defined shape. This query is answered by the selectiveuse of an enter button 118, a start arc 120 and an end arc button 122.If the point surveyed lies on a straight line the query is answeredsimply by touching the enter button 118. If the point is to lie on acurve then either the start arc button 120 or end arc button 122 ispressed. It is noted that a curved portion of the defined shape may bean actual arc of a circle, but more generally a curved portion is aportion that is not substantially straight and the curved portion doesnot have to be an arc of a circle.

Additionally, the right hand side 116 of input screen 107B illustrates aprompt for a vertical offset. For example, if the user is surveying thebase of a subgrade, and the user knows that the top of the pavement isfor example 0.25 meters higher than the subgrade, then the user canenter a vertical offset “VOff” of 0.25 as shown, representing the top ofthe pavement.

In the flow chart of FIG. 12 , the surveying of a position such asposition 1 is indicated at block 120, the addition of vertical offset isillustrated in the block 122, and the response to the query as towhether the point is part of a straight portion or a curved portion ofthe shape is indicated at block 124.

The shape fitting component may also query as indicated at block 126,whether the user wishes to enter a cross slope value associated witheach measured point, in order to generate an additional file which willautomatically control the cross slope of the civil engineering machine.

In this most simple example of defining a straight line portion of thedefined shape, an end point 2 of the straight line portion may besurveyed as illustrated in FIG. 14 , and a straight line portion 128 ofa defined shape may be defined joining the beginning and ending points 1and 2 of the straight line portion.

It is noted that in general the defined shape being defined is a threedimensional shape, wherein each surveyed or determined position has botha horizontal position in two dimensions as illustrated from the lefthand side of FIGS. 13 and 14 , and a vertical or elevation position.

Thus, even when defining a straight line portion such as 128, additionalpositions may be surveyed between the beginning and ending points 1 and2, which additional positions may for example be utilized simply toprovide elevation position data for the straight line portion 128. Ingeneral, as indicated at block 130 in FIG. 12 the user may selectwhether or not to use the data for any surveyed position, and as furtherindicated in block 132 the user may select whether to use data from agiven surveyed position only for purposes of defining elevation positionof the shape or only for purposes of defining horizontal position of theshape, or both.

As each surveyed position is added to the group of surveyed positionsfrom which the defined shape is to be defined, the algorithms containedin the software defining the shape fitting component 110 will define orredefine the defined shape based on the available data as indicated atblock 134.

At any time during the gathering of survey data defining the varioussurveyed positions, the shape fitting component may be prompted todisplay the defined shape as shown for example in FIG. 14 . As indicatedat block 136 the display may show the deviation 138 (see FIG. 14 ) ofany given surveyed point X from the defined line. As indicated at block140 the user may choose to delete a point, or to resurvey the positionof a selected point. If the user chooses to resurvey a position then theposition data for that point will be substituted for the originalposition data and then as indicated at block 142 the shape fittingcomponent 110 will redefine the defined shape 142 based upon themodified data.

As long as additional data for additional surveyed positions is to beadded, the process repeats by returning to block 120 and surveying thoseadditional positions.

As previously noted, the defined shape may include curved portions.Those curved portions may be adjacent to and extend from adjacentstraight portions, as for example previously shown in FIG. 11 . Also, acurved portion or an additional straight portion may be spaced from thefirst straight portion 128 of the defined shape.

As shown for example in FIG. 15 , additional points 3, 4, 5 and 6 havebeen surveyed. In the example of FIG. 14 , an additional straight linesegment is defined between points 3 and 4. There is a gap or spacingbetween points 2 and 3. A curved portion is defined by points 4, 5 and6.

In general there are several options for how to create a curved portionutilizing the shape fitting component. The choice will depend on theamount of data which is available to the user, and the type of curve tobe defined, though several options include:

-   -   1. If the curve is an arc, and if Start point (=PC) and End        point (PT) and the design radius are known and given to the        user, that is sufficient to define the arc.    -   2. If the curve is an arc, and if Start point and End point and        a third point which lays on the arc are given to the user, that        is sufficient to define the arc.    -   3. If the curve is an arc, and if Start point and End point are        not precisely defined, but a third point which lays on the arc        is given to the user, that is sufficient to define the arc.    -   4. If the curve is a more complex shape that is not an arc, and        if Start point and End point are not precisely defined and there        are more than 2 points on the curve (e.g. a spiral curve with        undefined radius), then an algorithm is used to define a curve        corresponding to the data points.    -   5. A complex curve may also be represented as a series of many        relatively short straight lines.

Regardless of which option is used, the user starts a curve by tappingon the “Start Arc” button 120 and takes the measurements for the varioussurveyed positions based on whatever information is available. Thealgorithms utilized by the shape fitting component 110 will alwayscreate a smooth shape which is tangential to the element measured beforethe curve starts and tangential to the element after the curve ends. Anysuitable mathematical method may be utilized to define a defined curvecorresponding to the series of data points. One suitable mathematicalmethod is a Bezier curve, which is an elegant method of approximatinglines between a flexible number of data points defining the curve. Thecalculated curve is very suitable for designing roadways and railways asit results in a smooth and homogenous line.

It is noted that in an actual field situation, the user may not know forcertain whether a given portion of the structure being surveyed is bestrepresented as a straight line portion or as a curved portion. In such acase it is better to define that portion of the structure as a curve andto provide at least four surveyed points. Also, if the user is notcertain where the start and end point of a curved portion resides, it isbetter to start the curve early and finish it later in order to generatea smooth transition between the straight and curved elements of thedefined shape.

If the curve changes direction, this is accomplished simply by startinga new curve at the point of inflection.

The curved portion is ended when the entire curve transitions into astraight line. At the end of the curved portion, the user presses the“End Arc” button 122 and the algorithm will automatically calculate thedefined curved portion such as 144 seen in FIG. 15 .

FIG. 16 illustrates a further continuation of the process where anadditional point 7 has been surveyed to define an additional straightline portion 146 between points 6 and 7. Thus, for example thestructures indicated in FIG. 16 might indicate the locations of curbingin a parking lot with a gap between points 2 and 3 for an entrance intothe parking lot.

As indicated at block 148 of FIG. 12 , the shape fitting component 110further provides for the editing of the vertical profile of the definedshape. For example, the user may be provided with construction plans forthe project which define the desired slope between various points on thedefined shape. Thus, any field measurements taken may be modified toconform them as desired to define a defined shape having the desiredvertical profile.

Once the defined shape has been fully defined, as indicated at block 150a shape storing component 150 of the control unit 107 stores in thememory 107C the data defining the defined shape. That defined shape ispreferably defined as a series of one or more straight line portionsand/or one or more curved portions. Each straight line portion may bedefined by a direction and a length. If the curved portion is an arc, itmay be defined by a radius of curvature and a length. If the curvedportion is a complex curve it may be defined in more complex format,such as by a Bezier curve or by other suitable curve fitting technique,or it may be defined as a series of many short straight line segments.Such data may for example be similar in format to the data shown in thefollowing Table I defining the shapes shown in FIG. 16 . The data ofTable I is provided as an example only, and is not intended to be in anyway limiting of the scope of the claims.

TABLE I Type of Ending Line/Arc Tangent SEGMENT Element Station NorthingEasting Length Out 128 Line 4.696 5849.596 3322.980 4.696 73.1432 NE 143Line 1.487 5851.695 3320.968 1.487 30.3803 NW 144 Curve 3.987 5852.6313318.822 2.500 77.4446 SW 146 Line 5.987 5852.206 3316.868 2.00 77.4446SW

After the defined shape is defined and stored in memory, it may be savedin either of two formats. First, the data gathered by the rover usingGPS co-ordinates may be saved in the GPS co-ordinates representing theshape in the reference system independent of the position andorientation of the civil engineering machine. In this first instance,the file may simply be loaded into controller 7 of the civil engineeringmachine and used without further transformation. Second, the data may besaved in a format like that of the Table above, defining the shape as aseries of straight and curved lines with lengths and directions. In thissecond instance, the shape file may be utilized like any otherpre-stored shape and may be selected and used. The selected shapedefined as a series of distances and directions in the reference systemof a civil engineering machine may be transformed into curve datarepresentative of the location and orientation of the selected shape inthe reference system independent of the civil engineering machine.

Alternatively instead of transferring the data from the rover controlunit 107 to the machine control unit 7, the civil engineering machinemay be provided with an interface or docking station 160 which allowsthe rover control unit 107 to be connected to the civil engineeringmachine. When the rover 100 is docked with the civil engineering machinethe rover can perform various functions on the civil engineeringmachine, including serving as one of the position sensors of the civilengineering machine and/or serving as at least a part of the controlunit of the civil engineering machine.

For example, as schematically illustrated in FIG. 17 , the rover 100 maybe constructed to be mounted on the chassis 2 of the civil engineeringmachine by engaging the rover 100 with the docking station 160, so thatthe receiver S100 of the rover 100 takes the place of the receiver S2 ofthe civil engineering machine. In this embodiment, when it is desired tosurvey various positions on the ground located remotely from the civilengineering machine, the rover 100 may be undocked and used to surveythose ground locations as indicated. Then the rover may be again dockedwith the civil engineering machine and serve in the role of one of thereceivers of the civil engineering machine. When docked in the dockingstation 160 the rover control unit 107 may be communicated with themachine control unit.

Further, as schematically illustrated in FIG. 18 , when the rover 100 isdocked with the civil engineering machine the rover control unit 107 maybe used as the machine control unit for the civil engineering machine,and the separate machine control unit 7 may be eliminated.

Thus it is seen that the apparatus and methods of the present inventionreadily achieve the ends and advantages mentioned, as well as thoseinherent therein. While certain preferred embodiments of the inventionhave been illustrated and described in the present disclosure, numerouschanges in the arrangement and construction of parts and steps may bemade by those skilled in the art, which changes are encompassed withinthe scope and spirit of the present invention which is defined by theappended claims.

What is claimed is:
 1. A method of controlling a self-propelled civilengineering machine to produce a shape for a structure to be produced ora ground surface to which changes are to be made based at least in parton a pre-surveyed site wherein a plurality of indicia have been placedon the ground surface identifying the locations of a series ofpre-surveyed points along the ground surface corresponding to thedesired shape, the method comprising: (a) defining a reference point ofthe civil engineering machine in a machine co-ordinate system; (b)determining with a field rover positions of at least some of the indiciain a reference system independent of a position and orientation of thecivil engineering machine; (c) creating a virtual stringline along whichthe reference point of the civil engineering machine is to move in thereference system independent of the position and orientation of thecivil engineering machine to create the desired shape; (d) determiningdata which defines a position of the reference point of the civilengineering machine in relation to the reference system independent ofthe position and orientation of the civil engineering machine; and (e)controlling the civil engineering machine with a machine control unitsuch that the reference point of the civil engineering machine movesalong the virtual stringline.
 2. The method according to claim 1,wherein: during step (b) the field rover is separate from the civilengineering machine.
 3. The method according to claim 1, wherein theindicia include pins or stakes placed into the ground surface.
 4. Themethod according to claim 1, wherein: step (c) includes determiningcurve data defining the virtual stringline at least in part based uponthe positions of at least some of the indicia determined in step (b). 5.The method according to claim 1, wherein: the curve data includes atleast one straight line portion and at least one curved portion.
 6. Themethod according to claim 5, wherein: at least one of the curvedportions is defined using an algorithm configured to define a smoothcurve.
 7. The method according to claim 1, wherein: the series ofpre-surveyed points along the ground surface corresponding to thedesired shape define a selected geometrical shape; and the methodfurther comprises: editing the selected geometrical shape.
 8. The methodaccording to claim 1, wherein: in step (d), an initial position of thereference point of the civil engineering machine in relation to thereference system independent of the position and orientation of thecivil engineering machine is not on the virtual stringline; and furtherincluding, prior to step (e), controlling of the civil engineeringmachine with the machine control unit in such a way that the referencepoint of the civil engineering machine moves to a point on the virtualstringline.
 9. A method of controlling a self-propelled civilengineering machine to produce a shape for a structure to be produced ora ground surface to which changes are to be made, the method comprising:(a) defining a reference point of the civil engineering machine in amachine co-ordinate system; (b) determining with a field rover positionsof a first plurality of points on the ground surface corresponding to afirst shape portion in a reference system independent of a position andorientation of the civil engineering machine; (c) determining with thefield rover positions of a second plurality of points on the groundsurface corresponding to a second shape portion in the reference systemindependent of the position and orientation of the civil engineeringmachine, the second shape portion being separated from the first shapeportion by a gap; (d) determining curve data defining a desired curvealong which the reference point of the civil engineering machine is tomove in the reference system independent of the position and orientationof the civil engineering machine to create the first shape portion andthe second shape portion; (e) determining data which defines a positionof the reference point of the civil engineering machine in relation tothe reference system independent of the position and orientation of thecivil engineering machine; and (f) controlling the civil engineeringmachine with a machine control unit such that the reference point of thecivil engineering machine moves along the desired curve to create thefirst shape portion and the second shape portion separated by the gap.10. The method according to claim 9, wherein: one of the first andsecond shape portions is a straight line.
 11. The method according toclaim 9, wherein: one of the first and second shape portions is a curve.12. The method according to claim 9, wherein: one of the first andsecond shape portions is a straight line and the other of the first andsecond shape portions is a curve.
 13. The method according to claim 9,further comprising: controlling a cross slope of the civil engineeringmachine as the civil engineering machine moves along the desired curve.14. The method according to claim 9, wherein: each of the first andsecond shape portions is a three dimensional shape.
 15. The methodaccording to claim 9, further comprising: displaying the first andsecond shape portions on a display.
 16. The method according to claim15, further comprising: editing at least one of the first and secondshape portions.
 17. The method according to claim 16, wherein: theediting includes deleting at least one point of the first plurality ofpoints.
 18. The method according to claim 16, wherein: the editingincludes resurveying at least one point of the first plurality of pointswith the field rover.